1. Field of the Invention
The present invention relates to an apparatus and a method for adhering woven or knitted light shielding velvet ribbons to a photographic film cassette, more particularly to an assembling method and apparatus suitable for adhering ribbons in a recess formed in a cassette half molded from plastics.
2. Description of the Related Art
In a conventional photographic cassette (herein referred to as cassette), a metal cassette body rotatably contains a plastic spool around which a photographic filmstrip (herein referred to as film) is wound. The cassette body is constituted of a cylinder made of metal plate and caps fitted on its both sides. A film passageway is formed in the cylinder between a pair of distal edges of the metal plate by bending the edges outward so as to define a spacing therebetween. A pair of strips of woven or knitted velvet ribbons for shielding ambient light, generally called "ribbons" are adhered respectively to these distal edges in order to prevent light from entering the inside of the cassette through the passageway. If the ribbon is shorter than the passageway, light would enter the cassette around the ribbon. In view of this, a ribbon having a length equal to or greater than the length of the cassette body is adhered to the passageway according to a ribbon adhering apparatus as disclosed in U.S. Pat. No. 4,891,089 (corresponding to Japanese Patent Laid-open Publication No. 63-74869).
Recently a cassette having a cassette shell molded from plastics has been utilized. In such a cassette, the cassette shell is constituted from a pair of cassette halves between which the spool is rotatably contained. In such a cassette, a film leader is advanced to the outside through the film passageway when the spool is rotated. In this cassette, the passageway is formed between a pair of channel-shaped recesses formed at the interface of the cassette halves.
However, in the above resinous cassette, the lengthwise range of the passageway is smaller than that of the cassette half. This is so because lateral walls, having a small thickness, must be formed in each cassette half. Accordingly, the above-mentioned ribbon adhering apparatus cannot be employed in a resinous cassette shell. Another ribbon adhering apparatus is disclosed in Japanese Utility Model Laid-open Publication No. 63-74638, in which the length of the ribbon to be adhered can be selected as desired. However, this apparatus also has disadvantages when used with a resinous cassette. In particular, the ends of the ribbon are not easily positioned precisely on the lateral ends of the channel-shaped recess of a resinous cassette half. Thus, lateral gaps may be formed which allow light to enter the cassette. Also, in the apparatus disclosed therein, the cassette must be kept from moving during adhesion of ribbon. This increases the time required for the process of adhering the ribbon to the cassette.